Tool changer employing automatic work indexing mechanism

ABSTRACT

The disclosure introduces a new concept in machining; that of the non-captive tool. A non-captive tool is herein defined as one which may undergo bodily movement, transversely of its own axis, relative to both the tool bearing structure which supports the tool in working position and a tool support structure which supports the tool in a non-working position adjacent the bearing structure. The non-captive tool is unrestrained against the aforesaid bodily movement except during that time the tool is actually working and, while working, the restraint imposed is due to engagement with the tool driving means. Accordingly, removal of the tool driving means from engagement with the tool frees the same for bodily movement which movement may, advantageously, be integrated with the movement of the tool driving means out of engagement with the tool.

United States Patent 51 Aug. 8, 1972 Cupler, II

[54] TOOL CHANGER EMPLOYING AUTOMATIC WORK INDEXING MECHANISM [72] Inventor: John A. Cupler, H, 10 Cupler Drive,

Cumberland, Md.

[22] Filed: Sept. 4, 1969 [21] App]. No.: 871,135 I Related US. Application Data [62] Division of Ser. No. 715,711, March25, l968,

Pat. No. 3,478,419.

[52] US. Cl ..29/26 A, 27/568, 408/4 [51] Int. Cl. ..B23q 3/157 [58] Field of Search ..29/568, 26; 408/4 [56] References Cited UNITED STATES PATENTS 3,259,957 7/1966 Stobbe ..29/26 3,238,615 3/1966 Leone et al ..29/568 Primary Examiner-Andrew R. lJuhasz Assistant Examiner-Z. R. Bilinsky Attorney-Colton and Stone ABSTRACT The disclosure introduces a new concept in machining; that of the non-captive tool. A non-captive tool is Q herein defined as one which may undergo bodily movement, transversely of its own axis, relative to both the tool bearing structure which supports the tool in working position and atool support structure which supports the tool in a non-working position adjacent the bearing structure. The non-captive tool is un- 4 Claims, 24 Drawing Figures PKTENTED 8'97? 3.681.829

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KH MS#8 Q1 Tn k 364 WORK 23 INDEX STATION CLAMP I TOOL CHANGER EMPLOYING AUTOMATIC WORK INDEXING MECHANISM This is a division of application Ser. No. 715,711, filed Mar. 25, 1968, now US. Pat. No. 3,478,419.

The disclosure is directed to methods and apparatus for automatically interchanging a plurality of non-captive rotary tools between working and non-working positions; for effecting tool interchange concomitantly with respective engagement and disengagement of working and non-working with a constantly driven input; for effecting infinitely variable infeed of the working tools; for automatically positioning a workpiece in accordance with pre-programmed operating cycles controlling a tool changer; for performing machining operations with a tool having a compound rotary input; and for transmitting a programmed cycle of operation from a master machining console to a plurality of slave machining centers.

The working and non-working tools in accordance with a first aspect of the invention relating to a tool changer are non-captively supported, in a horizontal position, on Vee bearings and a tool support rack, respectively. The tools are mounted on spindles which are adapted to be supported adjacent their outer ends on the support rack and at an intermediate portion thereof on the bearings. The bearings are of the Vee type and provide non-captive support for the tool spindles supported thereon to permit both rotary and reciprocating movement of the tools. Relative vertical movement between the rack and bearings results in an interchange of tools therebetween by virtue of the tools being lifted from either the bearings or the rack, depending on the direction of vertical movement.

At least one flexible driving member is constantly recirculated adjacent the bearings and is mounted for vertical movement with the tool support rack for movement into and out of driving engagement with the working tools simultaneously with the aforementioned tool interchanging operation.

A linearly reciprocable cam follower is mounted adjacent each tool bearing in coaxial alignment with that end of the tool spindle remote from the working end; whereby reciprocating and/or advancing movement of the followers will be transmitted through one end thereof to the working tools. An elongated cone cam is positioned to engage the other ends of the followers and reciprocate the same upon rotation of the cone. The cone is, additionally, mounted for axial translation to provide for controlled advance of the followers and tools engaged thereby. Simultaneous rotation and translation of the cone results in a constantly advancing reciprocating path of tool movement.

A work station is positioned adjacent each of the Vee bearings and includes a work clamping and indexing mechanism whose sequence of operation is integrated with, and controlled by, the operating cycles undergone by the tool changing mechanism.

A tool having a pair of telescoped spindles, each of which is adapted to receive a separate rotary input, is provided for use in certain special machining operations.

A second cone cam is mounted outside the confines of the tool changing mechanism for reciprocating one or a plurality of followers comprising the input to a closed hydraulic slave system whose output is adapted to actuate additional tools.

BACKGROUND OF THE INVENTION The invention relates, primarily, to tool changers of the type wherein a plurality of rotary tools are required to perform sequential operations on a single workpiece or a plurality of workpieces. Exemplary of the type machining operations that niay be performed on a single workpiece or a plurality of workpieces, in accordance with the invention, are drilling, boring, milling, grinding, reaming, etc. ln its broader aspects, it is within the contemplation of the invention to apply the principles herein disclosed to rotary tools in general and, more specifically, to working tools wherein some combination of rotary and reciprocating movement is desirable. As will be apparent from the ensuing description, the principles herein disclosed are also applicable to the interchanging and reciprocation of non-rotary tools.

Prior an tool changers of the more complex type commonly referred to as Machining Centers as well as greatly simplified versions thereof, have been known and used for years in machining operations that require the sequential use of rotary tools to perform various operations on a single workpiece. These prior art structures have, through the years, advanced from the simplest hand operated models, through semi-automatically operated devices to highly sophisticated automated tape-controlled tool changers. As mass production techniques have advanced, machine tool designers have attempted to keep pace with increasing requirements of shorter time cycles in tool changing operations by a variety of methods that diverge from, or ignore, the primary obstacle to the attainment of a virtually instantaneous tool interchange. This obstacle is the captive tool. The use of chucked, or captive, tools characterized not only the earliest tool changers but those in present day use.

The necessity of stopping rotation of a chuck and spindle duringa tool changing cycle with attendant decrease in production efficiency due to down time is normally regarded as axiomatic in the machine tool industry. Accordingly, prior efforts to reduce down time have been directed, primarily, to methods of shortening the cyclic time requirements in stopping rotation of the chuck, removing one tool from the chuck, substituting a second tool therefor and again engaging the chuck drive.

In addition to the conventional acceptance of a chucked tool as a necessary part of a tool changer, the indexing mechanism of the usual present day equipment holds the tools captive prior to the interchanging operation with a chuck. This makes it necessary to release the tools when it is desired to alter the sequence of operations that may be performed at the work station.

Another great disadvantage in known tool changers is the difficulty in some cases, and the impossibility in others, of obtaining perfect concentricity among the various tools that may be required to operate in a single position. This problem is greatly magnified in the case of miniature machining operations because even the minor eccentricities inherent in chucked tools, which may be tolerated in macro drilling, are multiplied beyond permissible tolerance ranges in the case of micro drilling or machining.

Inasmuch as chucked tools are intended to rotate concentrically with the axis of the rotating chuck, it is necessary to reposition the chuck any time it is desired to work on a new centerline or otherwise reposition the workpiece in relation to the chuck. This is not only time consuming, but allows for additional errors to be introduced in the repositioning step.

Known tool changers of the type to which the invention pertains normally utilize tool infeeding mechanisms which involve infeeding and/or reciprocation of the chuck and tool. Because of the fact that a tool will normally be advanced into the workpiece in a reciprocating manner to facilitate chip removal, the use of rotary cams having sequentially increasing cam follower lobes separated by cam flats have heretofore been regarded as one of the more desirable methods of infeeding and reciprocating tools. The greatest disadvantage in such a system of tool infeed is in the fact that, for a particular cam, the tool infeed program is established when the cam is installed and can only be varied by substituting a different cam. Thus, in the case of a tool changer where many different type operations are to be performed on a single workpiece; the various tools, each, require various rotational speeds, infeed rates and reciprocation cycles for maximum efficiency. This flexibility is virtually impossible to achieve in a tool changer using conventional camming arrangements wherein a plurality of tools are to perform a machining operation on a single workpiece after which time the same sequence of machining operations are to be performed at a different position on the same workpiece or on a separate workpiece. Accordingly, it is necessary to compromise the most efficient operating cycles for each of the particular tools in order to achieve a programmed control that is acceptable for all of the tools. The problem becomes more acute when changing over from machining one type material to another. In this case, it is usually necessary to substitute cams which is not only time consuming but requires the maintenance of a large number of precision cams which are quite expensive.

Another great disadvantage in conventional cam infeeding mechanisms is that the starting position of the tool infed thereby, is more or less fixed. Thus, for example, a tool actuated by a conventional cam infeed will always start at substantially the same point relative to the work station. This is disadvantageous where, for example, a new tool is intended to work within a previously formed bore or in a recess of indeterminate depth.

Among the many additional disadvantages in known cam infeed systems, in addition to the inability to change the infeed cycle that is built into the cam; are the inability to instantaneously change over from a reciprocating tool infeed to a non-reciprocating infeed, i.e., to separate the rises and falls built into a conventional cam; the inability to stop tool reciprocation either in or out of the hole; and the inability to infinitely control infeed rates.

A primary object of the invention is to provide a method of, and apparatus for, utilizing completely noncaptive tools in a tool changer whereby the same may be interchanged for sequential operations virtually instantaneously.

The invention is further directed to a method and apparatus for interchanging a plurality of tools between working and non-working positions in which the rotary tool driving means is automatically engaged and disengaged with respect to appropriate ones of the tools as an incident of the tool changing operation. in the case of non-rotary tools the rotary tool driving means may be engaged with the non-rotary tool and the drive thereto interrupted whereby the same merely holds the tool in position for the infeeding operations to be subsequently described.

An outstanding feature of the invention that is susceptible of use, not only with a tool changer involving a plurality of sequential operationsbut also with a single tool machining operation, is the method and apparatus relating to the tool infeeding mechanism herein disclosed. The tool infeed mechanism makes possible a method and apparatus whereby a plurality of sequentially operated tools may be infinitely and individually controlled in their infeeding operations that may include either reciprocating, reciprocating-advancing or straight advancing movement. The infeed mechanism thus makes it possible to separate the rises and falls inherently built into conventional cam infeeding mechanisms whereby, for the first time, a plurality of tools may be infinitely controlled by a single camming member which, in turn, may simultaneously control the operation of virtually any number of tools.

It is among the further objects of the invention to provide method and apparatus for non-captively supporting a plurality of tools adjacent a tool bearing adapted for non-captive tool support and interchanging tools therebetween; to enable the sequence of tool operation to be altered in any desired manner either under manual or automatic programming; to dispense with the necessity of stopping tool rotation prior to the initiation of a tool changing operation; to provide a tool changer wherein perfect concentricity among the various tools in the working position is assured, merely by controlling the diameter of the tool spindles; to provide a tool changer that is equally adaptable for precision machining in either macro or micro operations; to provide a novel cam infeeding arrangement requiring but a single cam to control the infeed of any desired number of tools; to provide a work station having means for cyclically indexing and clamping a workpiece in accordance with input signals derived from the tool interchange mechanism; and to provide method and apparatus for transmitting, not only programmed information but the work output derived therefrom, to a plurality of remotely located working stations.

The fact that the tool infeeding mechanism may be infinitely varied coupled with the fact that the rotational velocity of the tools may be infinitely controlled, permits the most desirable operating parameters for each particular tool to be pre-programmed into the machine.

SUMMARY OF THE INVENTION The invention is directed, primarily, to a tool changer which may be either semi-automatically controlled or completely automated under tape-controlled or digital programming.

The contrast between actual performances of the tool changer herein described and known tool changers, as regards overall speed of operation and accuracy of control, is such as to render present day tool changer principles obsolete.

The word tool," as used herein, refers not only to the actual tool itself, such as a drill, but also to the spindle on which the same is carried. It will be apparent that the working tool portion, itself, could be formed separately and mounted on the spindle or formed integrally therewith.

The tool changer, according to the invention, is provided with a plurality of horizontally arranged upwardly opening Vee bearings that are fixedly positioned adjacent their respective work stations for noncaptively supporting a spindle mounted tool on each of the bearings for combined rotary and reciprocating motion relative thereto. The fact that the tool bearing is fixed, relative to the work station, eliminates the introduction of any error in positioning a new tool in coaxial alignment with the working position of a previous tool based on the tool support bearing itself. Thus, if the tool spindle diameters of a plurality of tools are equal, their sequential placement in the same Vee bearing insures their positioning along the same axis as contrasted to the case of chucked tools wherein not only the tools but also either their chucks or the workpiece are moved relative to the work during each tool changing cycle.

A particularly desirable type machining operation requiring extreme accuracy of positioning that is virtually impossible to achieve without utilizing the principles herein disclosed, is the machining of a single hole having varying diameters relative to a common centerline. Thus, in making a synthetic yarn spinnerette, for example, where a countersink bore of relatively large diameter is to extend part way through the workpiece and the bore is to be continued through the workpiece with a much smaller bore; it is critical that the smaller bore be precisely on centerline with the larger bore to insure that the intersection of the two bores occurs in precise symmetrical relationship to the deepest penetration of the countersink portion of the larger .bore.

Additionally, in order to change the work centerline it is not necessary to substitute a tool having a spindle whose diameter differs from that of a previous tool by a known amount. Accordingly, the necessity for repositioning a chuck or a workpiece during a working cycle is eliminated along with the errors inherent in such a repositioning operation. The spindles themselves, having been previously machined to known diameters within known tolerances, thus provide a most attractive and expeditious manner of changing working centerlines in an accurate manner merely by manually or automatically substituting one tool for another.

The Vee bearings support the tool spindles adjacent an intermediate portion thereof and the outer ends of the tool spindles extend beyond the longitudinal confines of the bearings. The function of this relationship of parts is two-fold; first, each tool spindle extends far enough beyond the ends of the bearing, axially of the spindle, to permit axial reciprocation of the tool spindle relative to the bearing and; secondly, the unsupported ends of the spindle may be engaged by a support rack moving upwardly, relative to the bearing, to lift the tool from the bearing. Conversely, downward movement of the support rack relative to the bearing results in a tool being lifted from the rack by the bearing whereupon such tool is positioned coaxially with the position of the tool previously supported on the bearing.

The bearing support rack, previously referred to, comprises a generally rectangular frame having the longer sides thereof spaced apart a distance slightly exceeding the length of the Vee bearings. A plurality of upwardly opening recesses are formed in the upper surfaces of the support rack in paired alignment along the respective longer sides thereof. The tool spindles bridge the longer sides of the support rack by having their end portions supported in the paired recesses. The support rack is mounted for both vertical and horizontal movement relative to the bearings. Various pairs of recesses in the rack may be aligned with various ones of the bearings by horizontal movement of the support rack whereupon vertical telescoping movement of the support rack relative to the bearings either lifts a tool from each of the bearings or deposits a tool thereon depending upon the direction of vertical movement. Considering the tools to be in working position on the bearings, when a tool change is to effected; the support rack is vertically raised past the bearings to engage the outer ends of the tool spindles in the rack recesses and lift the tools from the bearings. After the support rack reaches its uppermost position above the bearings, the same is shifted horizontally to bring a new tool into alignment with each of the bearings. The support rack is then again lowered and the new tools are lifted from the rack by their engagement, adjacent the intermediate portions of the spindles with the bearings, as the rack is again lowered.

A constantly recirculating flexible driving member is mounted for bodily vertical movement with the support rack relative to the bearings. The driving member is so related to a plurality of idler pulleys and driving pulleys secured to each of the tool spindles that the same is brought into approximately l driving engagement with the driving pulleys of those tools positioned in the bearings when the support rack is in the lower position. Conversely, the flexible driving member is spaced from the tool driving pulleys when the rack is in the upper position. Thus, in a tool changing operation, the upward movement of the rack effects both a separation of the working tools from driving engagement with the recirculating member andremoval of the tools from the bearings. This action is immediately followed by a horizontal shift of the tool support rack to bring other tools into vertical alignment with the bearings after which time the rack is again lowered to position new tools in the bearings and entrain the driving member at least part way around their driving pulleys. Thus, it is apparent that the drive for the recirculating driving member need not be interrupted during the tool changing cycle. Accordingly, it will be appreciated that the non-captive manner of supporting the tools, both on the bearings and on the tool support rack, taken in conjunction with the arrangement of parts wherein the driving member may be constantly driven makes it possible to reduce the time requirements involved in changing tools to that involved in moving the rack upwardly, horizontally and downwardly a matter of a few inches. The actual time requirement for simultaneously changing a plurality of tools adjacent a like plurality of work stations may vary between 0.5 seconds and 3 seconds depending on the size tools being utilized.

The advantages in non-captively supporting the tools on their respective bearings are immediately obvious in that the same may be both rotated and reciprocated in relation to a fixed bearing. This assures perfect tool alignment at all times as contrasted with previously known tool changers wherein the tool supporting elements, i.e., the chucks, must not only reciprocate with the tool but must be repositioned during the tool changing operation which introduces errors in addition to those inherent in chucks which cannot provide infinite concentricity as among a plurality of rotating tools held in the same chuck.

The advantages in the non-captive manner of supporting the tools on the tool rack are apparent, in part, in that such is required to effect the very rapid tool interchange described above. A less obvious, but no less important, advantage lies in the fact that an operator may substitute new tools for those already on the rack merely by lifting the same from the rack and putting others in their place. This substitution can be made while the working tools are engaging the workpiece. Assume, for example, a tool changer having four work stations, four Vee bearings and a tool support rack having 12 pairs of aligned tool supporting recesses. In this case, three separate tools are designed to be supported at different times on each bearing for engagement with the workpiece. In the event that it may be desirable to use a fourth tool in connection with a particular operation being performed, the operator may merely substitute such a tool for one of the three tools that has already performed its work operation. Alternatively, in a particular case, it may be desirable to substitute a different tool for one of the three tools that would normally engage the workpiece. The ability to quickly substitute new tools for those already on the rack is very important where, as in the present case, a plurality of workpieces are undergoing simultaneous operations. Thus, if an operator were required to use a chuck key or equivalent tool support releasing device to remove and insert every tool, the number of tools that could be changed within a reasonable period of time would be severely restricted and, of course, completely inconsistent with the speed of operation made possible by the tool changer of the present invention.

A unique tool infeeding mechanism is described herein which relies on a single camming member to control the infeed of virtually any number of rotary tools. A cam follower is mounted adjacent each bearing for reciprocal movement in coaxial alignment with the tool adapted to be supported on the bearing for rotation in the manner previously described. The positioning of the followers relative to the bearings and the lengths of the tool spindles are such that when the followers are urged to their forwardmost positions in the direction of the work stations, the forward ends of the followers engage the rearward ends of the tool spindles and move the same forwardly to their forwardmost positions representing the maximum tool penetration into the workpiece. The permissible rearward travel of the followers allows the spindle mounted tools to be completely withdrawn from the workpiece. The novel infeeding mechanism herein described relates to the manner in which a single camming member is utilized to actuate the followers and tools to undergo any desired sequence or combination of reciprocating, advancing-reciprocating and constant advancing motion. The use of a cone cam to engage the rear ends of the followers makes possible the range of infeeding operations herein described.

The cone cam includes an elongated conical surface interrupted by an elongated discontinuity or cam flat which actually may assume a slightly concave configuration when viewed in elevation. The cone is mounted for both rotation about its axis and bodily translation along its axis. The rotation may occur alone, to impart reciprocating motion to the tool, or the cone may be simultaneously rotated and translated to concomitantly reciprocate and advance the tool, i.e., advance the path of reciprocating motion. Alternatively, the cone cam may be translated without rotation whereuponthe tools are advanced into the workpiece without reciprocation. All of the foregoing infeeding operations occur simultaneously with the tool rotation imparted thereto by the recirculating driving member in the manner previously explained. In those cases where it may be desirable to provide a virtually infinite infeed capability as between each of the working tools; a plurality of small cone cams, each having a different profile, may be mounted on the same shaft to coact with a different one of the working tools.

Tool reciprocation is normally desired, during the infeeding operation, in order to provide a period of time during which the tool may be cooled and chips removed from the workpiece by the flow of coolant onto the working area. A plurality of shallow grooves may be formed in the conical cam surface, if desired, to impart a series of very short reciprocating strokes to the tools during each rotation of the cam to facilitate chip breakage in addition to the much greater reciprocating stroke that occurs once during each cam revolution. This chip breaking reciprocation of the tools is an alternative feature of the invention and the reciprocation of the tool, in this case, normally occurs within the workpiece as contrasted to the larger stroke reciprocation occuring once during each cam revolution, wherein the tools are withdrawn from the workpiece for chip removal. 7

Each of the cam followers, corresponding in number to the Vee bearings, may be of different lengths so that their cone cam engaging ends are spaced equally from the corresponding portion of the elongated cone. Alternatively, the followers could be of equal length and their supports be staggered to achieve the desired spatial relationship between the followers and cone. As a third alternative; a plurality of cones, having different profiles, could be mounted on the same shaft for individual coaction with each of the working stations whereby each working tool would be infed by a different cone cam all of which would be under the same control as that described in connection with the single cam. The rotational and/or translational speed of the cone may be pre-programmed to correspond to the most efi'icient operating parameters for each tool which will be used in a series of machining operations. Thus, where three tools are to sequentially engage the same area of the workpiece as in drilling, reaming and burnishing a single hole for example, various rotational, reciprocating and/or infeeding rates are required for each tool to work at maximum efficiency. These known values may be pre-programmed whereupon the speed of the recirculating member and the cone rotation and/or translation are varied in accordance with each tool changing cycle. The manner in which such programming is effected will become more apparent in the following detailed description of operation. When changing over from machining operations on one type material to another, the ability to utilize a single control, the cone cam, which may be programmed to provide infinitely variable infeeding rates is of paramount importance in that nothing more than the resetting of the programming controls is necessary to insure maximum efficiency of operation for each tool in machining a different material.

In addition to the rotary and translatory motion that may be imparted to the cone to control tool infeed, the same is also mounted for movement transversely of the axis thereof toward and away from the cam followers. The purpose of this latter cone movement, which occurs once during each tool change cycle, is to remove the cone from proximity to the followers while the tool rack undergoes the horizontal and vertical movements previously described to effect the tool interchange between the bearings and the tool support rack. The cone may be moved toward and away from the followers by mounting the same for linear bodily movement on ways that extend parallel to the axis of the cam followers or the same may be mounted for bodily pivotal movement toward and away from the followers.

As previously alluded to, the followers and tools engaged thereby may be initially positioned at any desired infeeding point either within a recess or hole previously machined or at a desired point relative to a recess of in determinate depth. This initial positioning of the infeeding mechanism may be effected in one of two ways; first, the cone cam may be moved bodily toward and away from the followers to initially position the same; or the cone may be translationally shifted, along its own axis, to present a larger diametral surface of the cone to the followers at the time a particular machining operation is to be initiated. Where the cone is to be bodily moved toward or away from the cam followers to effect the desired starting point, removable stops may be provided to assure the proper positioning of the slide or pivoted member supporting the cone.

The tool changer is also provided with an additional recirculating driving member which may be used in conjunction with the previously described driving member to provide a compound rotary input to certain specialized tools as will be explained in greater detail as the description proceeds.

The aforementioned cone cam is integral with, or fixedly secured to, a shaft extending along the axis of the cone. The shaft is journalled in bearings supporting the cone and shaft for rotary and translatory motion. The shaft extends beyond one end of the cone for connection to the rotary and translatory motion imparting means and beyond the other end of the cone to support one or more auxiliary cone cams outside the confines of the tool changing mechanism previously described. The auxiliary cone may have any desired configuration in relation to the first cone and is, similarly, mounted for integral rotation and translation with the shaft. The purpose of the auxiliary cone is to actuate one or a plurality of followers whose output is impressed on a closed hydraulic slave system to transmit the same to any desired point. In some instances, the slave system is utilized in combination with at least one additional tool changing mechanism to provide the tool infeed therefor in a manner similar to that described above except that in the additional tool changing mechanism,

the tool follower infeed elements are advanced into the work by connection with the hydraulic slave system as by bellows, pistons or the like.

The slave system is particularly advantageously used in certain machining operations performed in connection with the tool changer mechanism on which the auxiliary cone is mounted and makes possible combined operations not previously attainable. One example of such a combined operation involving a feedback from the auxiliary cone to the primary, or master, tool changer relates to the simultaneous drilling of a single workpiece from opposite sides thereof wherein the opposed drills performing the drilling operations are perfectly concentric with each other or offset a predetermined amount either by manually offsetting the tools or varying the tool spindle diameters. This opposed drilling feature is made possible by positioning an additional Vee bearing on the opposite side of the workpiece from the Vee bearings previously described and in alignment therewith. A recirculating element, similar to that previously described, may be mounted to drive a drill spindle resting on the additional Vee bearing and the output of the auxiliary cone fed, by way of the hydraulic slave system, to the end of the drill opposite the workpiece. The drill being infed by the slave system may thus be reciprocated, reciprocated and advanced, or merely advanced into the workpiece in consequence of the movement of the auxiliary cone cam. The opposed drills may be reciprocated either in or out of phase depending upon the angular relationship of the cone flats on the two cones.

Additionally, the auxiliary cam and slave system may be used to impart the simple reciprocating or advancing motion to a non-rotary tool positioned either for operation in conjunction with the primary tool changer or in connection with a completely diverse operation.

As will become more apparent from an understanding of the overall disclosure; the slave system may be utilized not only in the specific manner above mentioned, but also to impart all of the movements from a master tool changing console to a plurality of slave consoles. Thus, the slave system may be incorporated not only with the auxiliary cone cam to transmit infeeding motions to a remote location, but also analogous systems may be appropriately positioned to transmit all of the motions undergone by the tool changer herein described to other similar tool changers.

DESCRIPTION OF THE DRAWINGS The manner in which the foregoing and other objects of the invention are made possible will become more apparent from the following detailed description when considered in conjunction with the drawings, wherein:

FIG. 1 is a front elevation of a tool changer constructed in accordance with the invention;

FIG. 2 is a side elevation, with parts broken away, as viewed from the right of FIG. 1;

FIG. 3 is a side elevation, with parts broken away, as viewed from the left of FIG. 1;

FIG. 4 is a rear elevational view of the tool changer shown in FIG. 1, with the cone cam in non-working position;

FIG. 5 is a top plan view of the tool changer mechanism, shown in FIG. 1, with the control consoles removes for clarity of illustration;

FIG. 6 is a fragmentary front elevation illustrating the drill placement rack and horizontal support rack positioned for a machining operation;

FIG. 7 is a view similar to FIG. 6, but illustrating the placement and support racks positioned for a tool changing operation;

FIG. 8 is a sectional view taken along with line 8-8 of FIG. 6 illustrating the mechanism for raising and lowering the drill placement rack;

FIG. 9 is a sectional view taken along the line 99 of FIG. 6 illustrating a flexible drive coupling used to transmit driving torque between relatively moveable shafts;

FIG. 10 is a sectional view taken along the line 10- 10 of FIG. 9;

FIG. 11 is a sectional view taken along the line 11 11 of FIG. 5;

FIG. 12 is a view similar to FIG. 11 but illustrating the cone cam as being shifted rearwardly from the FIG. 1 1 position, as during a tool changing operation;

FIG. 13 is a view similar to FIG. 11, but omitting the cone cam, which illustrates a different type tool that may be provided with a compound rotary input;

FIG. 14 is a detail view, partially in elevation and partially in section, of the compound tool shown in FIG. 13;

FIG. 15 is a sectional view taken along the line 15- 15 of FIG. 14;

FIG. 16 is an exploded diagrammatic view of the various driving means employed in the tool changer;

FIG. 17 is a side elevation of a work holder employed with the tool changer herein disclosed;

FIG. 18 is an elevational showing of the work holder of FIG. 17 as viewed from the left, thereof;

FIG. 19 is a top plan view of the work holder shown in FIG. 17;

FIG. 20 is a fragmentary elevational depiction of the work holder as viewed from the right of FIG. 17;

FIG. 21 is a sectional view taken along the line 21 21 of FIG. 18;

FIG. 22 is a sectional view taken along the line 22 22 of FIG. 21;

FIG. 23 is a diagrammatic illustration of the control circuitry embodied in the present tool changer; and

FIG. 24 is a largely diagrammatic illustration of the manner in which a hydraulic slave system may be used with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 and 5-7, an automatic tool changer constructed in accordance with the present invention is depicted generally at 10 and includes a work table 12, work stations 14, Vee tool bearings 16, tool positioning mechanism 18, tool infeed mechanism 20 and tool drive means 22.

Work stations 14, each, includes a work clamping and indexing mechanism, generally indicated at 24, which is actuated by air pressure at predetermined times in the cycle of operation to be subsequently described.

Tool positioning mechanism 18 includes a vertically movable placement rack 26 supporting a horizontally slidable tool support rack 28 thereon for vertical move ment therewith. The Vee bearings 16 are secured to work table 12 in position to receive various ones of tools 30 thereon when placement rack 26 is in the lower position shown in FIGS. 1, 6 and 11. Tool support rack 28 is horizontally movable relative to vertically movable rack 26 in stepwise increments corresponding in distance to the spacing between preselected ones of tool support grooves or recesses-32 formed in support slide 28. Drive belt 34, mounted for vertical movement with rack 26, extends beneath idler pulleys 36. Adjacent pairs of idler pulleys 36 are positioned one on either side of the bearings and deflect the belt into approximately l80 engagement with pulleys 38 fixed to the spindles 40 of those tools 30 vertically aligned with Vee bearings 16 when the placement rack is in the lower position illustrated in FIGS], 6 and 1 1 Tool infeed mechanism 20 includes a cone camp 42 integral with cone shaft 44 that is mounted in bearings 46 carried by cone support slide 48 for rotary and translational movement relative thereto. Cone support slide 48 is pivotally mounted on rod 50 carried by table 12 for rocking movement, whereby cone cam 42 may be positioned to engage and disengage cam follower infeed elements 52 supported in bearing blocks 54 adjustably mounted on table 12. Cam follower infeed elements 52 are aligned with the spindles 40 of those rotary tools resting on Vee bearings 16. Cone cam 42 includes a major peripheral, substantially conical surface and a minor concave surface portion extending axially of the cone cam. When cone cam 42 is in the forward position of FIG. 11, rotation of the same results in reciprocation of the follower infeed elements and those tools resting on the Vee bearings as the cam followers cyclically engage the arcuate and concave portions of the rotating cone. Translational movement of the cone in the direction of the smaller end thereof, to the left as viewed in FIGS. 1 and 5, results in an incremental increase in the forward infeed of the tools toward the work stations during each revolution of the cone. Stated differently, the tools are reciprocated by the rotation of the cone and the path of reciprocation is incrementally fed forwardly into the work piece by virtue of the cone translation which continually presents a larger diameter portion of the cone for engagement with the follower infeed elements. The cone shaped surface of the cone cam may, if desired, be provided with a plurality of small longitudinally extending grooves .56 which act as chip breakers by providing a number of very short reciprocating tool strokes of short duration during each revolution of the cam. In many cases, grooves 56 will not be required and the major peripheral portion of the cone will be smoothly contoured to present a true conical surface.

TOOL BEARING SUPPORTS Tool bearings 16 are of the Vee type disclosed and claimed in U.S. Pat. No. 2,607,244 and are fixedly secured to work table 12 as by threaded fasteners or the like. The Vee bearings are positioned to support spindles 40 of tools 30 in a horizontal position for combined rotary and reciprocating motion as described in U.S. Pat. No. 2,607,244. It will be noted that, because of the horizontal disposition of the bearings, the tools will be supported thereon even though tool driving pulleys 38 secured to tool spindles 40 are not engaged by the driving belt 34 as during a tool shifting operation to 

1. In combination with a tool changer including a movable member for withdrawing a previously used tool from a bearing and for inserting another tool therein thereby successively interchanging tools between working and non-working positions; a work holder, comprising; means for fixedly positioning a workpiece on said work holder adjacent the tool working position, means for locking said workpiece in fixed position, means for indexing said workpiece, and control means responsive to tool withdrawing movement for controlling said locking and indexing means.
 2. The combination of claim 1 wherein said control means includes means maintaining said workpiece locked in fixed position through at least two tool interchanges.
 3. The combination of claim 2 wherein said control means includes mEans for releasing said workpiece from its locked position and actuating said indexing means.
 4. The combination of claim 3 wherein the tool changer further includes continuously operating means for driving said tools. 